nail² v [T] to fasten something to something else with a nail 钉，将…钉牢: The windows were nailed shut. 窗户都被钉牢了。
nail sb/sth ↔ down 1 to fasten something down with nails 将〔某物〕钉住 2 to reach a final and definite decision about something 把…确定下来: After three weeks they finally nailed down the details of the deal. 三星期后他们终于把交易的细节确定了下来。